I had the same experience yesterday using FC13 with the RNG110. Once
I made sure it worked direct to the TV (required a call to Comcast). I
followed the Firewire wiki, plugreport worked, test_mpeg2 worked, file
played with VLC, channel change with 6200ch worked, mythbackend setup
detected but mythfrontend tuner status always showed error. After much
frustration, I stopped and restarted the mythbackend service from the
gnome admin - services menu. It may have been a coincidence but it's
working great now.